The Wattstopper UT-355-3 is a low-profile ultrasonic line-voltage ceiling occupancy sensor built for automatic lighting control in large open commercial spaces such as warehouses, gymnasiums, and open-plan offices. Operating at 100347VAC, it provides a 2,000 sq ft ultrasonic detection zone to capture minor movement across wide coverage areas. Line-voltage operation allows direct switching without a separate low-voltage control system, simplifying specification and installation.